Joule-Thomson effect i.e., a throttling process is a constant __________ process.
Entropy
Temperature
Internal energy
Enthalpy
Correct Answer :
D. Enthalpy
Related Questions
Melting of ice exemplifies a/an
Adiabatic process
Endothermic reaction
Exothermic reaction
Process involving a chemical reaction
A gas has a volume of 27.3 c.c. at 0°C. Its volume at 10°C (if pressure remains unchanged) will be __________ c.c.
2.73
28.3
273
283
Which is not a refrigerant?
SO2
NH3
CCl2F2
C2H4Cl2
For a cyclic process, a fixed ratio between heat and work
Always exists
May exist
Never exists
Is difficult to predict
For a constant volume process
dE = CpdT
dE = CvdT
dQ = dE + pdV
dW = pdV
At equilibrium condition, the chemical potential of a material in different phases in contact with each other is equal. The chemical potential for a real gas (μ) is given by (where, μ = standard chemical potential at unit fugacity (f° = 1 atm.) and the gas behaves ideally.)
μ° + RT ln f
μ°+ R ln f
μ° + T ln f
μ° + R/T ln f
y = specific heat ratio of an ideal gas is equal to
Cp/Cv
Cp/(CP-R)
1 + (R/CV)
All (A), (B) and (C)
On opening the door of an operating refrigerator kept in a closed room, the temperature of the room will
Increase
Decrease
Remain same
Increase in summer and will decrease in winter
Heat evolved/absorbed during conversion of a substance from one allotropic form to another is termed as the heat of
Fusion
Vaporisation
Transition
None of these
Pick out the wrong statement
Phase rule variables are intensive properties
Heat and work are both state function
The work done by expansion of a gas in vacuum is zero
CP and CV are state function
Which is not constant for an ideal gas?
(∂P/∂V)T
(∂V/∂T)P
(∂P/∂V)V
All (A), (B) & (C)
An ideal gas is taken around the cycle ABCA as shown in P-V diagram below: The work done by the gas during the cycle is equal to
12 P1V1
6 P1 V1
3 P1V1
P1 V1
If we increase the pressure on a substance (which is at its triple point), then the triple point
Increases
Decreases
Remains unchanged
May increase or decrease; depends on the substance
The change in Gibbs free energy for vaporisation of a pure substance is
Positive
Negative
Zero
May be positive or negative
Gibbs-Duhem equation
States that n1dμ1 + n2dμ2 + ....njdμj = 0, for a system of definite composition at constant temperature and pressure
Applies only to binary systems
Finds no application in gas-liquid equilibria involved in distillation
None of these
The internal energy of an incompressible fluid depends upon its
Pressure
Temperature
Both (A) & (B)
Neither (A) nor (B)
Specific volume of an ideal gas is
Equal to its density
The reciprocal of its density
Proportional to pressure
None of these
Which of the following is an undesirable characteristic of a refrigerant?
It should be non-explosive
It should have a sub-atmospheric vapor pressure at the temperature in refrigerator coils
Its vapor pressure at the condenser temperature should be very high
None of these
The adiabatic throttling process of a perfect gas is one of constant enthalpy
In which there is a temperature drop
Which is exemplified by a non-steady flow expansion
Which can be performed in a pipe with a constriction
In which there is an increase in temperature
Equilibrium constant of a reaction varies with the
Initial concentration of the reactant
Pressure
Temperature
None of these
At the critical point of a substance
The surface tension vanishes
Liquid and vapour have the same density
There is no distinction between liquid and vapour phases
All (A), (B) and (C)
The compressibility factor for an ideal gas is 1. Its value for any other real gas is
1
< 1
> 1
Either (B) or (C), depends on the nature of the gas
Requisites of a reversible process is that the
System and surroundings pressure be equal
Friction in the system should be absent
System and surroundings temperature be equal
None of these
The total change in the enthalpy of a system is independent of the
Number of intermediate chemical reactions involved
Pressure and temperature
State of combination and aggregation in the beginning and at the end of the reaction
None of these
For a reversible process involving only pressure-volume work
(dF)T, p < 0
(dF)T, p > 0
(dF)T, p = 0
(dA)T, v < 0
For equilibrium process (i.e. reversible) in an isolated system
ds = 0
ds < 0
ds > 0
ds = Constant
Which of the following is Clausius-Clapeyron Equation for vaporisation of an ideal gas under the condition that the molar volume of liquid is negligible compared to that of the vapor?
d ln p/dt = Hvap/RT2
d ln p/dt = RT2/Hvap
dp/dt = RT2/Hvap
dp/dt = Hvap/RT2
Maxwell's relation corresponding to the identity, dH = dS = Vdp + Σμi dni is
(∂T/∂V)S, ni = -(∂P/∂S)V, ni
(∂S/∂P)T, ni = (∂V/∂T)P, ni
(∂S/∂V)T, ni = (∂P/∂T)V, ni
(∂T/∂P)S, ni = (∂V/∂S)P, ni
Gibbs free energy (G) is represented by, G = H - TS, whereas Helmholtz free energy, (A) is given by, A = E - TS. Which of the following is the Gibbs-Helmholtz equation?
[∂(G/T)/∂T] = - (H/T2)
[∂(A/T)/∂T]V = - E/T2
Both (A) and (B)
Neither (A) nor (B)
Pick out the wrong statement.
The conversion for a gas phase reaction increases with decrease in pressure, if there is an increase in volume accompanying the reaction
With increase in temperature, the equilibrium constant increases for an exothermic reaction
The equilibrium constant of a reaction depends upon temperature only
The conversion for a gas phase reaction increases with increase in pressure, if there is a decrease in volume accompanying the reaction